How much does using a CPU radiator as intake affect GPU temperature?

[moobox]

I'm wondering if all of the warm/hot air the radiator is blowing into a case will have a major impact on GPU temperatures while everything is under load, particularly if that CPU radiator is front mounted.

Anybody have any experience with testing this?

 

[the nerd 389]

What radiator, fans, CPU, radiator orientation (X-flow top-bottom, X-flow bottom-top, IO at bottom, or IO at top), and flow rate?

Also are you overclocking the CPU, and are there any other intake fans?

In the OC tests I've seen, the radiator warms the intake air by as much as 10-15C. Non-OC builds can be around 5-10C. Because of the way temps work, that will be the increase in GPU temps if no other intakes are involved.

 

[moobox]

What radiator, fans, CPU, radiator orientation (X-flow top-bottom, X-flow bottom-top, IO at bottom, or IO at top), and flow rate?

Also are you overclocking the CPU, and are there any other intake fans?

Corsair H100i v2 with stock SP120L fans
All other fans are AF120s
7600k (will be OC @ 4.8GHz)

My P400S which is on order only supports front moutned radiators and I'm trying to decide how to configure the cooling.

I want to use front mounted rad as intake as to better cool the CPU, just wondering if it will affect temperatures for my STRIX 980 with a very minor OC.

Or should I intake through 2x120mm fans through the top of the case and exhaust through the radiator at the front.

Hope that is more specific. Not using push/pull on rad btw.

 

[the nerd 389]

That build would require you to increase the fan speeds on both the H100i and the 980 Strix in order to keep the VRMs within acceptable limits. You only have about 10C of headroom with that card under a gaming load. If you run torture tests, you may not be able to keep the VRMs from exceeding 100C.

Running the top fans as intakes isn't generally a good idea either, as it would require the rear fan to also be an intake in order to avoid recirculation. The GPU heat would then be carried through the CPU cooler, and the cooler won't be happy about that. If the coolant temperature exceeds 40C, the fans will jump to max speed to avoid damaging the pump. If you overclock at all, that's not difficult to hit, and the result is an obnoxiously loud PC.

That fan setup would also push GPU heat through the PSU, and that's never a good idea.

 

[moobox]

That build would require you to increase the fan speeds on both the H100i and the 980 Strix in order to keep the VRMs within acceptable limits. You only have about 10C of headroom with that card under a gaming load. If you run torture tests, you may not be able to keep the VRMs from exceeding 100C.

Running the top fans as intakes isn't generally a good idea either, as it would require the rear fan to also be an intake in order to avoid recirculation. The GPU heat would then be carried through the CPU cooler, and the cooler won't be happy about that. If the coolant temperature exceeds 40C, the fans will jump to max speed to avoid damaging the pump. If you overclock at all, that's not difficult to hit, and the result is an obnoxiously loud PC.

That fan setup would also push GPU heat through the PSU, and that's never a good idea.

Thankfully the PSU will be in it's own eco system (under a shroud, fan drawing from bottom of the case).

That all makes sense thanks for the info.

So given the circumstances, what configuration would you recommend?

Also keep in mind that with the P400S TGE, both of the spots for fans at the top of the case have removable covers/dust filters that can be removed individually. So I could use the back fan and one of the two top fans as intake, and the other spot just blocked off with the included cover. Is that a good idea or do you have another suggestion?

 

[the nerd 389]

There is no good option for a radiator in that case. I would get a different case before getting the water cooler.

If the top fans are intakes, and the rear fan is exhaust, the heated air will leave the rear and get caught in the top intake.

If the rear fan is an intake, and the top fans are intakes, any GPU heat that manages to get out the back of the case will get caught in either the rear intake or the top intakes and get pushed over the other components and through the CPU cooler.

If the rear is blocked off, and the top fans are intakes, you'll have less recirculated air, but you'll also have a hotspot in the lower center of the case. That's going to take a toll on the drives.

If one of the top fans is blocked off, the other is an intake, and the rear is an intake, you'll still recirculate the GPU heat.

Basically, there are no good options. Anything you try to do with a radiator in that case will give you problems.